Scientist have long known that plants can sense Carbon Dioxide (CO2), and will rapidly open and close stomata (microscopic pores located on it's leaves shown in the highly magnified video below) as a reaction to the CO2 level detected, however "why" CO2 levels caused plant Stomata to open and close was a mystery until a team of researchers published a paper in Science Advances journal, describing the triggering/inhibiting mechanisms that allow plants to sense CO2 concentration and the downstream reactions that cause plants to breath via stomata.
Infrared Thermal Imaging was used to identify a CO2 insensitive Arabidopsis mutant plant with elevated leaf temperatures. The team then confirmed the high leaf temperature mutant didn't respond to changes in ambient CO2 level concentration. Once isolated, the research team was able to identify the DNA sequence causing the genetic mutation (a Raf-like protein kinase), named it "HT1" for "high leaf temperature 1", and worked backwards from there.
Since the stomatal pores control plant water loss, the sensor is vital for water management and holds implications for climate-induced drought, wildfires and agricultural crop management.
"For each carbon dioxide molecule taken in, a typical plant loses some 200 to 500 water molecules to evaporation through the stomatal pores," said Schroeder, Novartis Chair and faculty member in the Department of Cell and Developmental Biology. "The sensor is extremely relevant because it recognizes when CO2 concentrations go up and determines how much water a plant loses as carbon dioxide is taken in."Researchers Identify Elusive Carbon Dioxide Sensor in Plants that Controls Water Loss | Mario Aguilera – UC San Diego Today